Spinal cord injury (SCI) results in severe somatosensory and locomotor impairments. The project will investigate the role of glutamate receptors in chronic pand pharmacological techniques. The rats used will receive a spinal contusion injury, which best resembles blunt impact trauma in human SCI. Mechanical and thermal allodynia will be tested behaviorally. Extracellular recordings of spinal cord neurons in anesthetized rats will be used to test the following hypotheses: 1) Spinal cord injury produces central sensitization of dorsal horn neurons, which can be measured by electrophysiological techniques. 2) Increased activation state of ionotropic (NMDA and non-NMDA) glutamate receptors following SCI contributes to central sensitization and thus to CCP. The Specific Aims are: 1) To analyze SCI-evoked changes of responsiveness of nociceptive spinal dorsal horn neurons to peripheral mechanical and thermal stimuli. 2) To determine the contribution of ionotropic glutamate receptors in SCI-evoked changes in nociceptive dorsal horn neurons. These results will provide important new information on the electrophysiological and pharmacological mechanisms of chronic central pain after SCI. They will also provide valuable insight into the potential therapeutic value of ionotropic glutamate receptors as targets for pain relief after SCI. [unreadable] [unreadable]